Biomarkers of toxicity in Clarias gariepinus exposed to sublethal concentrations of polycyclic aromatic hydrocarbons

Physiological, biochemical and histological indices in Clarias gariepinus broodstock, and teratogenic indices in embryos exposed to sublethal concentrations of naphthalene, phenanthrene and pyrene were investigated in 2014 using a static-renewal bioassay protocol. Phenanthrene (1.41 mg l^?1) was the most toxic, followed by pyrene (1.53 mg l^?1) and naphthalene (7.21 mg l^?1), based on 96 h LC50 values. Hepatosomatic indices were significantly higher in naphthalene- and pyrene-treated males compared with solvent controls, whereas fecundity in females was significantly lower by factors of 2.4 (naphthalene), 2.8 (phenanthrene) and 2.4 (pyrene), compared with controls. Catalase levels were lower in female phenanthrene-treated fish compared with controls. Histological alterations observed in PAH-treated fish include oedema, inflammatory cells, epithelial lifting and hyperplasia in the gills, vacuolation, haemosiderin pigments and sinusoidal congestion in the liver, and degenerated zona radiata in the ovary. Teratogenic effects were not observed, as evidenced by the lack of histological alterations in embryos spawned from pre-exposed broodstock. Sex-specific responses and the utility of biomarkers at cellular and individual levels of organisation are therefore demonstrated for holistic evaluations of polycyclic aromatic hydrocarbons in ecotoxicological studies.     

Microclimate and tree community linked to differences in lepidopteran larval communities between forest fragments and continuous forest

Aim  We aim to assess the impact of forest fragmentation on lepidopteran larval community and study the associations of microclimate and tree community with lepidopteran assemblage.
Location  Kibale National Park, Uganda.
Methods  We investigated the effects of forest fragmentation on leaf herbivory, density of lepidopteran caterpillars, species richness and diversity as well as the composition of herbivorous lepidopteran larval community. Microclimate, size of the fragment, distance to the continuous forest, and tree diversity were studied as possible explanatory factors. We sampled 10 Neoboutonia macrocalyx Pax. (Euphorbiaceae) trees in each fragment during dry and rainy season, total of four times, in a year to cover the seasonal variation.
Results  The rates of herbivory, total larval density and species richness were significantly lower in the forest fragments than in the continuous forest but species diversity expressed as Fisher's alpha did not differ. The dominance structure and community composition of the larval communities in the fragments was different from that of the continuous forest. None of the differences we observed were related to the fragment area or distance to the continuous forest. Instead, we found an indication of association between the herbivore and the tree communities. The fragments had significantly lower humidity during most of the day and higher temperature during the afternoons (14–17 h), which might partially explain the differences in lepidopteran larval communities.
Main conclusions  Decreased larval density and species richness as well as differences in the community composition and structure all highlight the importance of large continuous forest areas for maintaining larval biodiversity.     

Herpetomonas roitmani (Fiorini et al., 1989) N. Comb.: A Trypanosomatid with a Bacterium-like Endosymbiont in the Cytoplasm

The trypanosomatid previously described as Crithidia roitmani is characterized here at the ultrastructural and biochemical levels. The data indicates that the parasite belongs to the Herpetomonas genus, and we therefore suggest the flagellate to be denominated as Herpetomonas roitmani n. comb. Cladistic analysis of isoenzyme data generated by eight different enzymes showed that the parasite presented a distinct banding pattern and could be grouped with some Herpetomonas spp., but not with Crithidia spp., used as reference strains. Accordingly, when the parasites were grown for longer periods in Roitman's defined medium, expontaneous differentiation from promastigotes to opisthomastigotes (typical of the Herpetomonas genus) occurred. Transmission electron microscopy revealed the presence of bacterium-like endosymbionts in the cytoplasm of all evolutive forms of the parasite. All morphological alterations characteristic of endosymbiont-bearing trypanosomatids could be observed.     

Long lasting impact of forest harvesting on the diversity of herbivorous insects

Many of the protected forest areas in Uganda have been subject to logging in the past. It is known that logging changes communities, but how long these changes last is unclear. Most of the studies on butterflies and moths have looked at the effects of logging relatively shortly (<15 years) after the logging took place. In this study we investigated community of herbivorous lepidopteran larvae and its temporal dynamics in a natural forest and three differently managed forest compartments after 40 years of regeneration. We collected samples of larvae from the leaves of Neoboutonia macrocalyx Pax. between April 2006 and March 2008 in Kibale National Park, Western Uganda. Herbivory, density of larvae, and species richness were significantly lower in logged compartments than in natural forest. Furthermore, the community composition differed significantly between the logged compartments and the natural forest. There was seasonal variation in larval density, species richness and diversity. In species richness and diversity the variation was synchronous in all the study areas, but larval density did not vary synchronously across the compartments, probably due to the impact of logging on the environment. We also observed changes in the community composition during different seasons in all the study areas. We attribute the long term impact of logging to the hindered regeneration of logged compartments and recommend restoration activities to help to return the logged areas closer to the natural state.     

辽宁地区毛腹种蝇的生态学调查

经过1963—64年在辽宁本溪新岭对毛腹种蝇Hylemya (Chionomyia)vetula(Zett,1838)进行生态学调查的结果,说明本种主要以成蝇越冬,多在室外活动;以蛹期越夏:10月上旬最早出现(17℃),秋末初冬大批羽化,10月中旬至11月中旬形成了第一个成蝇高峰,翌年3—4月是雌蝇产卵时期,活动频繁,雌蝇数量较多,形成了第二个成蝇高峰。于5月上旬成蝇绝迹(22℃),成蝇出现季节全长为7个月。 幼虫滋生于人粪和猪粪中。成蝇取食人粪、猪粪和牛粪。因此是一种在卫生上有一定重要性的蝇种。 三龄幼虫:肛板显然大形而向两侧突出,这点有别于种蝇属(Hylemya)的各巳知常见种的幼虫形态,但易被误认为花蝇属(Anthomyia)。它同七星花蝇(Anthomyia imbrida)和横带花蝇(Anthomyia illocata)相似,但是有以下区别:(1)小锥形的腹突、副腹突显然位于亚腹突一线的背方:(2)腹垫仅具等大的小刺,中央区无较大形的棘:(3)后肛疣仅有较大的丘状隆起,没有象花蝇属已知常见种幼虫的后肛疣那样尖而明显;(4)后气门间距约为后气门直径的1—2倍。     

本溪地区蚊虫初步调查

本溪地区的蚊虫过去未有过文献报告。我们于1957—1958年,在本溪地区(本溪市、本溪县)进行了蚊虫的初步调查。经两年的调查已发现的蚊种,有按蚊属1种,伊蚊属4种,库蚊属6种,共计11种。其名称如下:     

Few immigrant phytophagous insects on woody plants in Europe: legacy of the European crucible?

Exotic phytophagous insects are invading forest ecosystems worldwide. So far, 109 invasive insects on woody plants, 57 from North American (NA), and 52 from Asia (A) have established populations in European forests. Four orders account for about 84% of the immigrants: Homoptera 39%, Lepidoptera 13%, Coleoptera 19%, and Hymenoptera 13%. The majority of these invasive species (63% of NA and 77% of A) live on deciduous trees, of which 36% have been introduced from NA and Asia. The remaining insect species (37% NA and 25% A) live on various conifers, of which 53% have also been introduced. Most (57%) of the NA insects feeding on coniferous plants live upon their introduced, native host plants. These data suggest that many NA immigrant phytophagous species in Europe have been successful in establishing permanent populations because their native hosts preceded or accompanied them into Europe and/or were asexually reproducing species. We propose that fewer invasive phytophagous insects have become established in European compared to North American woodlands because of the unique legacy of the European Pleistocene/Holocene crucible (i.e. endless cycles of populations contracting into highly disparate, dispersed metapopulation refugia and eventually expanding out of them) on European species and ecosystems that caused highly diminished heterogeneity. This translates to fewer and less penetrable tri-trophic niches in Europe due to fewer and less available host plants, but greater zootic resistance per niche derived from more competition-hardened competitors and possibly natural enemies. Moreover, many European species are probably superior invasion specialists because the crucible favored traits that are conducive to success in highly subdivided, and extinction-prone metapopulations: asexual reproduction, polyploidy, and other traits especially conducive to persistence under stress, and explosive growth/spread under amelioration.